I have a strange behavior on my notebook.
After simply creating the environment I called the function
learn = cnn_learner(data, models.vgg19_bn).load('best_model_adapted_2')
to load a model created from another team, but this resulted in the title error.
The first execution the function tried to download the vgg19_bn model from download.pytorch.org, but was stopped after some time due to very slow downloading.
Not sure if there is something worng in the cache or elsewhere.